Alveolar Defects Research Articles

64 Finite Element Analysis of a Porous Dual Component 3D-Printed Bone Graft for Alveolar Ridge Augmentation

OBJECTIVES/GOALS: Our goal was to assess the ability of a 3D-Printed dual cover-core design alveolar ridge bone graft, to withstand the average maximum masticatory force of a healthy person. To this end, we characterized the materials, ran a finite element analysis (FEA) model, and validated it using a resin 3D-printed version tested under compression with strain gauges. METHODS/STUDY POPULATION: A tricalcium-phosphate/hydroxyapatite paste and mixed methacrylated alginate-gelatin were used for the core, and polycaprolactone for the cover. These were characterized using ASTM standards D695 and D638 for compression, tensile, and rheological testing. Then we converted cone CT-scan images of a mandibular alveolar ridge defect to an .stl file, and designed the cover and core in Meshmixer. The model was then imported into ANSYS 11.0, and a downward compression force of 500 N, the maximum masticatory force of a healthy adult, was applied on the graft and mandible’s top ridge. The different models included solid and porous covers and cores, as well as comparing screws on one or both sides of the cover, then validated by compressing a resin 3D-printed versions. RESULTS/ANTICIPATED RESULTS: The FEA model provided maximum displacements, Von Mises stress (VMS), and stress/strain values for each model. The highest maximum displacement was found on the solid covers with a combination of both buccal and lingual screws, at 0.162 mm. The lowest maximum displacement was found in the porous cover at 0.085 mm. All VMS values were below the tensile yield strength, meaning that the materials would not yield. The highest maximum stress was found on the porous cover at 13.52 MPa, the lowest was 1.06 MPa on the cover with no screws. The highest strain was found on the porous model at 0.010, which was 5.6x higher than the solid cover. The porous cover also showed less stress shielding, thus allowing a beneficial mechanical stimulation of the bone, and the lowest maximum displacement, possibly due to flexion through the pores. DISCUSSION/SIGNIFICANCE: Preliminary FEA models demonstrated that for the considered materials, a cover-core design of the mandibular implant would sustain the desired 500 N of force without yielding. The porous cover provides the most benefits, causing the least stress shielding and allowing diffusion of biological factors to support the osteoinductive role of the core.

Unilateral alveolar cleft size on prenatal 2-D ultrasonography predicts cleft of the secondary palate in fetal unilateral cleft lip: A Pilot Study.

Prenatal diagnosis of cleft palate (CP) is challenging. The current study's objective was to investigate if prenatal alveolar cleft width is associated with the likelihood of a cleft of the secondary palate in unilateral cleft lip (CL). The authors reviewed 2D US images in fetuses with unilateral CL from 1/2012-2/2016. Images of the fetal face were obtained with a linear and/or curved probe in the axial and coronal planes. Measurements of the alveolar ridge gap were taken by the senior radiologist. Post-natal phenotype findings were compared with prenatal findings. Thirty patients with unilateral CL met inclusion criteria; average gestational age was 26.67 ± 5.11 weeks (range 20.71, 36.57 weeks). Ten fetuses were found to have an intact alveolar ridge by prenatal US; postnatal exam confirmed intact secondary palate in all. Small alveolar defects <4 mm were noted in 3 fetuses; postnatal examination documented CP in a single patient. CP was confirmed in 15 of the remaining 17 fetuses who had alveolar cleft width >4 mm. An alveolar defect ≥ 4 mm on prenatal US was associated with greater likelihood of a cleft of the secondary palate (c 2 (2, n=30) = 20.23, p<.001). In the setting of unilateral CL, prenatal US documentation of alveolar defects ≥4 mm are highly predictive of the presence of a cleft of the secondary palate. Conversely, an intact alveolar ridge is associated with an intact secondary palate.

Volumetric Analysis of Unilateral Alveolar Bone Defect Using Modified Subtraction in Older Chinese Patients.

A large number of older patients (≥13y old) with alveolar clefts missed the optimal alveolar bone grafting time period in China. This study aimed to determine the accuracy and repeatability of modified computer-aided engineering subtraction for volumetric measurement of these patients. In addition, the study aimed to determine whether the volume of defect is correlated with cleft type (cleft lip and alveolus, cleft lip and palate), cleft location, age, and sex. Preoperative computed tomography data from 100 patients of unilateral alveolar cleft patients without secondary alveolar bone grafting were measured using 2 methods. The maxillary resin model around the alveolar cleft was printed using the 3-dimensional (D) printing method, and the volume of the defect was measured using the drainage method. In the modified subtraction method, Mimics software was used to simulate fracture filling by layer drawing, and the defect volume was determined by subtracting the preoperative fracture template from the filled 3D skull template. The mean time taken to calculate an alveolar cleft defect volume by modified subtraction method was 3.2 minutes. The average defect volume measured using the 3D printing and modified subtraction methods were 1.58±0.41 and 1.55±0.42cm 3 , respectively. Findings suggest that cleft location and age do not affect the defect volume of older patients with alveolar cleft, unlike cleft type and sex. The modified computer-aided subtraction method provides good accuracy, consistency, and reproducibility in measuring alveolar ridge defect volume. Moreover, this method is more efficient and cost-effective than the 3D-printed model method.

Alveolar bone defects around mandibular anterior teeth in Class I, II, and III malocclusions: a retrospective CBCT evaluation

Background: The aim of this study was to quantitatively and qualitatively evaluate alveolar defects of mandibular anterior alveolar bone in three different types of malocclusion with cone-beam computed tomography (CBCT) by an observational cross-sectional study.

Efficacy of Demineralized Bone Matrix for Revision Alveolar Bone Grafting in Patients Previously Treated with Bone Morphogenetic Protein 2 (BMP-2).

This study investigates the effectiveness of demineralized bone matrix (DBX) to close alveolar clefts in patients previously treated with bone morphogenic protein-2 (BMP-2) who remained with bone nonunion. This is an IRB-approved retrospective, single-center study. This study was conducted at a tertiary academic center. We searched for all surgical encounters with the Current Procedural Terminology (CPT) code 42210 from the years 2013-2019. Included patients were diagnosed with cleft alveolus, previous BMP-2 exposure and required revision bone grafting during mixed dentition for persistent alveolar defects. 17 patients underwent revision alveolar bone grafting (ABG) with either DBX (n = 10) or autograft (n = 7) to repair persistent bony cleft. The primary study outcome measured was alveolar bone graft revision failure described as continued alveolar nonunion. The median age at revision ABG was 13.1 ± 3.3 years, with a mean follow-up time of 4.9 years (1.1-9.2 years). Patients were 53% male, 47% had a unilateral cleft lip and alveolus. 58.8% of patients were treated with DBX in the cleft, 41.2% treated with autograft from iliac crest. Overall, 11.8% (n = 2) of all revisions failed, requiring a second revision. The average time to reoperation was 2.06 years, and both were re-grafted with autograft. There was no statistically significant difference between the type of bone graft source used and the failure rate obtained (P = .1544). DBX and autologous iliac crest bone grafts achieve similar alveolar union rates during revision ABG in patients treated with previous BMP-2 to the alveolar cleft.

Accuracy of Critical Care Ultrasonography Plus Arterial Blood Gas Analysis Based Algorithm in Diagnosing Aetiology of Acute Respiratory Failure.

Lung ultrasound when used in isolation, usually misses out metabolic causes of dyspnoea and differentiating acute exacerbation of COPD from pneumonia and pulmonary embolism is difficult, hence we thought of combining critical care ultrasonography (CCUS) with arterial blood gas analysis (ABG). The objective of this study was to estimate accuracy of Critical Care Ultrasonography (CCUS) plus Arterial blood gas (ABG) based algorithm in diagnosing aetiology of dyspnoea. Accuracy of traditional Chest X-ray (CxR) based algorithm was also validated in the following setting. It was a facility based comparative study, where 174 dyspneic patients were subjected to CCUS plus ABG and CxR based algorithms on admission to ICU. The patients were classified into one of five pathophysiological diagnosis 1) Alveolar( Lung-pneumonia)disorder ; 2) Alveolar (Cardiac-pulmonary edema) disorder; 3) Ventilation with Alveolar defect (COPD) disorder ;4) Perfusion disorder; and 5) Metabolic disorder. We calculated diagnostic test properties of CCUS plus ABG and CXR based algorithm in relation to composite diagnosis and correlated these algorithms for each of the defined pathophysiological diagnosis. The sensitivity of CCUS and ABG based algorithm was 0.85 (95% CI-75.03-92.03) for alveolar (lung) ; 0.94 (95% CI-85.15-98.13) for alveolar (cardiac); 0.83 (95% CI-60.78-94.16) for ventilation with alveolar defect; 0.66 (95% CI-30-90.32) for perfusion defect; 0.63 (95% CI-45.25-77.07) for metabolic disorders.Cohn's kappa correlation coefficient of CCUS plus ABG based algorithm in relation to composite diagnosis was 0.7 for alveolar (lung), 0.85 for alveolar (cardiac), 0.78 for ventilation with alveolar defect, 0.79 for perfusion defect and 0.69 for metabolic disorders. CCUS plus ABG algorithm is highly sensitive and it's agreement with composite diagnosis is far superior. It is a first of it's kind study, where authors have attempted combining two point of care tests and creating an algorithmic approach for timely diagnosis and intervention.

Finite element analysis of stress in oral mucosa and titanium mesh interface

BackgroundThe stiffness of titanium mesh is a double-blade sword to repair larger alveolar ridges defect with excellent space maintenance ability, while invade the surrounding soft tissue and lead to higher mesh exposure rates. Understanding the mechanical of oral mucosa/titanium mesh/bone interface is clinically meaningful. In this study, the above relationship was analyzed by finite elements and verified by setting different keratinized tissue width in oral mucosa.MethodsTwo three-dimensional finite element models were constructed with 5 mm keratinized tissue in labial mucosa (KM cases) and 0 mm keratinized tissue in labial mucosa (LM cases). Each model was composed of titanium mesh, titanium screws, graft materials, bone, teeth and oral mucosa. After that, a vertical (30 N) loadings were applied from both alveolar ridges direction and labial mucosa direction to stimulate the force from masticatory system. The displacements and von Mises stress of each element at the interfaces were analyzed.ResultsLittle displacements were found for titanium mesh, titanium screws, graft materials, bone and teeth in both LM and KM cases under different loading conditions. The maximum von Mises stress was found around the lingual titanium screw insertion place for those elements in all cases. The keratinized tissue decreased the displacement of oral mucosa, decreased the maximum von Mises stress generated by an alveolar ridges direction load, while increased those stress from labial mucosa direction load. Only the von Mises stress of the KM cases was all lower than the tensile strength of the oral mucosa.ConclusionThe mucosa was vulnerable under the increasing stress generated by the force from masticatory system. The adequate buccal keratinized mucosa width are critical factors in reducing the stress beyond the titanium mesh, which might reduce the titanium exposure rate.

The Guided Bone Regeneration of a Large, Noncontained Maxillary Anterior Perforation Defect: A Case Report.

The reconstruction of alveolar ridge defects can be challenging, especially when the lesion is large, noncontained, and located in the esthetic region. The present report describes the guided bone regeneration (GBR) procedure and prosthetic rehabilitation of a severe perforation defect in the anterior maxilla. Clinical and radiographic evaluations of the lesion indicated an endodonticperiodontal origin, and biopsy results confirmed the absence of malignancy. GBR was performed with the use of cortical mineralized freeze-dried bone allograft (FDBA) combined with recombinant human platelet-derived growth factor-BB (rhPDGF-BB) and a resorbable collagen membrane without the use of tenting or fixation screws. Six months after GBR, CBCT revealed adequate bone fill for the placement of 4.1 × 10-mm or 4.1 × 12-mm dental implants. The implant surgery was fully guided with a two-stage approach. After 10 months of healing, the implants were loaded with a screw-retained porcelain partial denture. The staged GBR approach, using a combination of FDBA, rhPDGF-BB, and a resorbable membrane without the use of tenting or fixation screws, resulted in significant bone fill, successful implant placement, and a functional and esthetic implant-supported prosthesis.

Prospects of buccal fat pad use for the treatment of alveolar bone ridge defects

Prospects of buccal fat pad use for the treatment of alveolar bone ridge defects

Comparative evaluation of regenerative potential of injectable platelet-rich fibrin and platelet-rich fibrin with demineralized freeze-dried bone allograft in the treatment of intrabony defects: A randomized controlled clinical study.

Injectable platelet-rich fibrin (i-PRF) being in liquid form keeps graft particles clumped together forming agglutinated steak of bone graft. It has been shown to contain more platelets and long-term deliverance of growth factors in comparison with platelet-rich fibrin (PRF). The aim of the present study was to assess regenerative potential of i-PRF and comparing it with PRF, along with demineralized freeze-dried bone allograft (DFDBA) in the treatment of intrabony alveolar defects. Thirty defect sites in 15 patients with bilateral intrabony defects were assigned randomly into two groups (Group I (Control group)- DFDBA + PRF and Group II (Test group)-DFDBA + i-PRF). Gingival index (GI), plaque index (PI), pocket probing depth (PPD), and relative attachment level (RAL) were recorded at baseline, 3 months, and 6 months. Linear bone growth (LBG) was recorded radiographically at baseline and 6 months. ANOVA test and post hoc Tukey test were used to assess intragroup comparison of clinical parameters. Paired t-test was used to assess intragroup comparison of the radiographic parameter. Unpaired t-test was used to assess intergroup variations in all the clinical as well as radiographic parameters. Statistically significant PPD reduction (P = 0.005) and RAL gain (P = 0.003) were found in Group II than in Group I, and no significant difference was found in other parameters. Percentage LBG was higher in Group II than Group I but the difference was not statistically significant. i-PRF with DFDBA showed more favorable results as compared to PRF with DFDBA in the management of intrabony periodontal defects.

Evaluation of autogenous tooth graft in regeneration of periodontal vertical alveolar defects: clinical, radiographic, and experimental study

Evaluation of autogenous tooth graft in regeneration of periodontal vertical alveolar defects: clinical, radiographic, and experimental study

Alveolar cleft reconstruction with vomerine bone: two surgical procedures in one step: a case series

Aim: Iliac crest (IC) is the most common source of bone for alveolar cleft repair, as it allows for harvesting a large amount of cancellous bone with a high rate of favorable outcomes. Its drawback is the donor-site morbidity. We propose a new technique for alveolar cleft grafting using vomerine bone (VB), which, through bone grafting, reconstructs the alveolus with the VB and simultaneously corrects the nasal septum deviation. Method: We performed 18 alveolar reconstructions with VB in patients with a small bony defect and septal deviation, which would benefit from septoplasty. A matched control group with IC bone grafting was selected. Panoramic X-rays were used for vertical assessment of ossification with the Bergland scale and CT scans for the evaluation of the thickness of the grafted area in the VB and IC groups and compared with an independent samples T-test. A paired T-test compared angular measurements of the septal deviation pre- and post- vomerine grafting. Results: All grafts healed uneventfully, with no complications at the donor site and respiratory function was improved. There was no statistically significant difference in ossification height between VB and IC, the alveolar thickness at the occlusal and middle third was higher with IC. Septal deviation was reduced significantly. Conclusion: Alveolar graft from VB seems to be a viable alternative to IC in patients who present with a mild bony alveolar defect in addition to septal deviation, allowing combined procedures while reducing the morbidity of the donor site.

Preoperative CBCT Guided Bone Regeneration Combined with Concentrated Growth Factor Applied in the Implantation of Maxillary Teeth with Insufficient Bone Mass.

It was to explore the application effect of cone beam computed tomography (CBCT) guided bone regeneration (GBR) combined with concentrated growth factor (CGF) in the implantation of maxillary teeth with insufficient bone mass. 78 patients with single maxillary anterior tooth loss and labial alveolar defects in Dazhong Stomatological Hospital were retrospectively analyzed and randomly divided into groups A and B. Both groups were treated with surgical methods of GBR at the same time of implantation. Group A: CGF fibrin fluid and Bio-Oss bone powder, covered with CGF membrane on the surface to guide bone regeneration. Group B: Bio-Oss bone powder was implanted and covered with Heal All collagen biofilm. The horizontal bone width, keratinized gingival width, bone plate thickness, implant margin results, and alveolar ridge width were analyzed at 3 and 6 months before and after the operation in both groups. 6 months after the operation, the difference in the indexes between the two groups was evident; and in group A, the indexes had an obvious difference in contrast with those before operation; the healing rate of soft tissue was 100% in group A and 80% in group B, which was significantly different (P < 0.05). Preoperative CBCT GBR combined with CGF can promote the bone formation content of guided regeneration of bone defects in the maxillary teeth region.

Efficacy of recombinant human bone morphogenetic protein-2 for bone regeneration in alveolar defects: A protocol for systematic review and meta-analysis.

There is still a lack of credible evidence in the literature regarding the effectiveness of recombinant human bone morphogenetic protein 2 (rhBMP-2) in bone regeneration of alveolar bone defects. Therefore, the purpose of this study is to evaluate the efficacy and safety of rhBMP-2 in autogenous bone graft in bone regeneration of alveolar bone defects and to provide basis for clinical practice. As of March 2023, two independent investigators will identify target literature by searching seven major databases (EMBASE, Google Scholar, PubMed, Cochrane Library, Wan Fang, CNKI, and Web of Science). All clinical cohort studies evaluating the efficacy of rhBMP-2 will be included. The outcomes of the study include changes in the depth of the dental pocket at the involved site, increased clinical attachment levels, patient satisfaction, and adverse events. The Cochrane risk of bias tool will be independently used to evaluate the risk of bias of included randomized cohort studies by two reviewers. A modified version of the Downs and Black tool is adopted to evaluate the quality of nonrandomized cohort studies. We hypothesized that rhBMP-2 plays an active role in bone regeneration in alveolar bone defects. It is worthy to critically review the evidence of the assessment of rhBMP-2 to inform clinical practice.

A Comparative Volumetric Assessment of Cancellous and Cortico-Cancellous Bone Graft in the Management of Unilateral Alveolar Cleft Defect using Cone Beam Computed Tomographic Scan-A Randomized Controlled Trial.

The most commonly preferred procedure for surgical correction of alveolar bone defect and restoration of bony contour is anterior iliac crest graft. Since the ancient time, cancellous bone graft is considered as a gold standard, but it has a high resorption rate and many other disadvantages, and hence we conducted this study to evaluate the efficacy of Cortico-cancellous bone graft harvested from anterior iliac crest to find out whether it can be used as a substitute for cancellous bone graft or not. The objectives of present study were to compare and evaluate the bone bridge formation rate, resorption rate, and uptake of bone graft at recipient site using cancellous and corticocanellous bone graft harvested from anterior iliac crest for complete unilateral cleft alveolus defects. Total 20 patients were divided into two groups by lottery method of randomization. Each group comprises of total 10 patients treated with cancellous bone graft in group 1 and corticocancellous bone graft in group 2 patients harvested from anterior iliac crest. Preoperatively and postoperatively CBCT scans were taken for each patient to calculate the volume of cleft defect and volume of newly formed bone after 6 months, respectively. Grafting fill rate was calculated and mean graft filling rate observed in the patients of group 1 was 1.14±0.03, and in patients of group 2, it was 1.17±0.03. The mean bone bridge formation rate observed in the patients of group 1 was 91.85±0.81 and in patients of group 2 it was 87.89±0.75. The mean bone resorption rate obtained in the patients of group 1 was 18.74±0.42 and in patients of group 2 it was 16.87±0.52. The present study concluded that accurate estimation of the amount required for bone grafting in the alveolar cleft can be performed by CBCT scan data using Planmeca Romexis viewer version 5.0 software. Even though the corticocancellous bone graft has some drawbacks, it is equally good as cancellous bone graft because of its less resorption than cancellous bone graft and can be considered as a second best option for secondary alveolar bone grafting.Clinical trial registration no (REF/2020/09/031605)/(CTRI/2020/09/028001).

Platelet-rich fibrin combined with a particulate bone substitute versus guided bone regeneration in the damaged extraction socket: An in vivo study.

It has been proposed that platelet-rich fibrin (PRF) can be used to support bone regeneration during alveolar ridge augmentation. The aim of this study was to determine whether an approach utilizing PRF provides similar performance to the established guided bone regeneration (GBR) procedure. Two-wall defects were surgically created in beagle dogs and treated in three experimental groups: (i) a sticky bone (SB) substitute prepared using liquid PRF and deproteinized porcine bone mineral (DPBM); (ii) SB covered with solid PRF compressed into a membrane; and (iii) GBR performed using DPBM covered by a collagen membrane. Quantitative reverse-transcription polymerase chain reaction was applied to the specimen after 1week of healing, and microcomputed tomography (micro-CT) and histological outcomes were analysed after 8 weeks of healing. Compared with GBR, PRF resulted in a moderate increase in the expression levels of osteoblast and osteoclast markers, osteocalcin, and calcitonin receptor. Moreover, PRF modestly increased angiogenesis and the inflammation markers vascular endothelial growth factor (VEGF) and IL-6. Micro-CT and histological analyses confirmed the expected increased alveolar ridge area, with no significant differences between the three groups. Consistently, graft consolidation, as indicated by new bone formation at the defect site, did not differ significantly between groups. The present results demonstrate that PRF-based approaches perform comparably to the established GBR procedure in terms of the consolidation of DPBM in two-wall alveolar defects.

Comparison of conventional impression making and intraoral scanning for the study of unilateral cleft lip and palate.

Patients with cleft lip and palate (CLP) encounter various problems, including disorders related to feeding, esthetics, and pronunciation. We compared two impression methods, conventional impression making and intraoral scanning, to study unilateral cleft lip and palate (UCLP). Patients with UCLP (n=7) were selected, and palatal impressions were taken by two steps: (1) impressions were obtained using an addition silicone rubber impression material, and a plaster model was prepared and (2) optical impressions were obtained using a desktop three-dimensional (3D) scanner and stereolithography (STL). Data were generated by two impression system combinations through STL. The results were analyzed using the Kruskal-Wallis or Mann-Whitney U test. There were no significant differences in the dimensions of the models between both groups. The measured depth of the alveolar cleft defects was deeper in the plaster model group (STL) than in the intraoral scanner group (STL). Digital models may prevent the risk of aspiration and respiratory disorders by using impression materials for preoperative jaw treatment of newborns and infants. We compared the results of both impression methods in the same patient and found that a shift to the 3D printer model is a safe alternative for preoperative jaw correction, as evidenced from the amount of tissue displaced due to the pressure applied during impression taking. In the future, we would like to conduct clinical research with a larger sample size of CLP patients to further corroborate these findings.

Reconstruction of vertical alveolar ridge deficiencies utilizing a high-density polytetrafluoroethylene membrane /clinical impact of flap dehiscence on treatment outcomes: case series/

ObjectivesThe aim of this study was to evaluate the effects of membrane exposure during vertical ridge augmentation (VRA) utilizing guided bone regeneration with a dense polytetrafluoroethylene (d-PTFE) membrane and a tent-pole space maintaining approach by registering radiographic volumetric, linear and morphological changes.MethodsIn 8 cases alveolar ridge defects were accessed utilizing a split-thickness flap design. Following flap elevation VRA was performed with tent-pole space maintaining approach utilizing the combination of a non-reinforced d-PTFE membrane and a composite graft (1:1 ratio of autogenous bone chips and bovine derived xenografts). Three-dimensional radiographic evaluation of hard tissue changes was carried out with the sequence of cone-beam computed tomography (CBCT) image segmentation, spatial registration and 3D subtraction analysis.ResultsClass I or class II membrane exposure was observed in four cases. Average hard tissue gain was found to be 0.70 cm3 ± 0.31 cm3 and 0.82 cm3 ± 0.40 cm3 with and without membrane exposure resulting in a 17% difference. Vertical hard tissue gain averaged 4.06 mm ± 0.56 mm and 3.55 mm ± 0.43 mm in case of submerged and open healing, respectively. Difference in this regard was 14% between the two groups. Horizontal ridge width at 9-month follow-up was 5.89 mm ± 0.51 mm and 5.61 mm ± 1.21 mm with and without a membrane exposure respectively, resulting in a 5% difference.ConclusionsWith the help of the currently reported 3D radiographic evaluation method, it can be concluded that exposure of the new-generation d-PTFE membrane had less negative impact on clinical results compared to literature data reporting on expanded polytetrafluoroethylene membranes.

The allogeneic shell technique for alveolar ridge augmentation: a multicenter case series and experiences of more than 300 cases

PurposeAllogeneic cortical bone plates (CP) might be used for alveolar ridge augmentation as an alternative to autogenous grafts (AG) and bone substitutes (BS). We report about a multicenter case series and our experiences of more than 300 cases using CP and the shell technique for reconstruction of the alveolar process to illustrate surgical key steps, variations, and complication management.MethodsDifferent types of alveolar ridge defects were augmented using the shell technique via CP. The space between the CP and the alveolar bone was filled with either autogenous or allogeneic granules (AUG, ALG) or a mixture of both. Implants were placed after 4–6 months. Microscopic and histological assessments were performed. In addition, space filling using AUG, ALG and bovine BS was discussed.ResultsScanning electron microscopy demonstrated the compact cortical structure of CP and the porous structure of ALG allowing micro-vessel ingrowth and bone remodeling. Histological assessment demonstrated sufficient bone remodeling and graft resorption after 4–6 months. In total, 372 CP cases and 656 implants were included to data analysis. The mean follow-up period was about 3.5 years. Four implants failed, while all implant failures were caused by peri-implantitis. Next, 30 CP complications were seen, while in 26 CP complications implant placement was possible. CP rehydration, stable positioning by adjusting screws, smoothing of sharp edges, and a tension-free wound closure were identified as relevant success factors. Space filling using ALG and a mixture of AUG/ALG resulted in sufficient bone remodeling, graft resorption and stability of the augmented bone.ConclusionsCP and the shell technique is appropriate for alveolar ridge augmentation with adequate bone remodeling and low complication rates. Allografts can prevent donor site morbidity and therefore may decrease discomfort for the patient.

Alveolar Repair Using Cancellous Bone and Beta Tricalcium Phosphate Seeded With Adipose-Derived Stem Cell.

Adipose-derived stem cells (ADSCs) have been subject of several studies due to their abundance, ease of preparation, and application in bone regeneration. We aim to compare effectiveness of alveolar reconstruction utilizing human cancellous freeze-dried graft (HCG) and beta tricalcium phosphate (BTP), both seeded with human ADSC (hADSC) and autologous bone graft (ABG). A 5 × 5 mm alveolar defect in 36 male Wistar rats were treated using: ABG (C), HCG-hADSC (H1), and BTP-hADSC (H2). At 1 and 8 weeks after surgery, runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osterix (OSX), and bone morphogenetic protein 2 (BMP2; g/mL) were quantified using immunohistochemistry, while bone tissue volume (BV, mm3), bone tissue volume fraction (BF, percentage), and trabecular thickness of bone (TT, mm) were assessed using micro-computed tomography (CT). One week after surgery, H2 was higher in RUNX2, OSX, ALP, and BMP2 than C (P < .05). Only RUNX2 and OSX were found to be higher in H1 than C, while ALP and BMP2 were higher in H2 than H1. Micro-CT revealed that H2 had a higher TT than C and C had a higher TT than H1 (P < .05). Eight weeks after surgery, both H2 and H1 was higher in RUNX2, OSX, ALP, and BMP2 than C (P < .05). RUNX2 and BMP2 were found to be higher in H1 than H2. Micro-CT revealed that H2 had higher BV and TT than C and H1 (P < .05). Exogenous hADSC strengthened the effectiveness of HCG and BTP to accelerate osteogenesis, osteoconduction, and osteoinduction. The latter was the most successful in bone formation, followed by HCG and ABG.